1. Field of the Invention
The present invention relates to electrostatic generators and, more particularly, to an improved high-voltage electrostatic generator having a plurality of electrostatic energy collection means around the circumference of the contra-rotating apparatus.
2. Description of the Background
Electrostatic generators are well known and have been commercially available for over a century. Their purpose is to convert mechanical energy, such as that delivered through a rotating shaft by an electric motor or a manual crank, into high-voltage, low-current electrical energy. Electrostatic energy is an important constituent of many modern technologies, including high-energy physics and electronic medical diagnostics.
An early electrostatic generator was invented by J. Wimshurst in England in 1883. The Wimshurst generator consists of two contra-rotating disks mechanically connected around the same shaft and mechanically driven by belts and pulleys. Each of the disks contains an equal number of evenly spaced regions called sectors around its periphery, on which a conducting foil is applied. The contra-rotating disks with conducting foil sectors are closely spaced to induce an electrostatic charge between them.
Referring now to FIG. 1, a prior art Wimshurst generator is shown with the contra-rotating disks 10, 20 presented as concentric and a plurality of foil sectors 12, 22 spaced evenly there about. It is to be understood that in this prior art embodiment the disks are of equal diameter with an equal number of evenly spaced conductive foil sectors 12, 22. Two neutralizing bars 31, 34 with end contact brushes 32, 33 and 35, 36, respectively, ground and neutralize charged foil sectors 12, 22 as they come into contact. In operation, when mechanical rotational energy is applied to the shaft from a hand crank, an electric motor, a flywheel, or any other source, two identical functions take place on each contra-rotating disk 10, 20, one producing a positive electrostatic charge and one producing a negative electrostatic charge. A region of positively charged foil actors on one disk is brought near a region of neutral foil sectors on the other disk. The positive foil sectors induce a negative charge in the nearby neutral foil sectors on the other disk. The positive charged foil sectors pass under the next adjacent contact brush, e.g, brush 35 of the arm of neutralizing bar 34 which discharges the positive surface electrostatic charge. The formerly neutral foil sectors 12 are now negatively charged, and as they move in the opposite direction from the positively charged foil sectors on the other disk and approach neutral foil sectors. Now these negatively charged foil sectors 12 act as the charged surface to induce a positive electrostatic charge in the neutral foil sectors 22 on the first disk 20 when they touch a contact brush of the second neutralizing bar 34. As the disks turn, the neutralizing bars 34, 31 become energy producing systems, one always producing a positive electrostatic charge and one producing a negative electrostatic charge. Given the above-described configuration, the rotating foil sectors on both disks 10, 20 will reach a point where they both carry a positive electrostatic charge in one segment. Likewise, the opposing foil sectors on both disks will both carry a negative electrostatic charge in an opposite segment. Collectors 41, 44 with end contact brushes 42, 43, 45, 46 are located in these two segments collect the respective charges. The result is a high-voltage electrostatic differential. The charges derived from collectors 41, 44 can be stored in capacitors for discharge of high energy, and in traditional systems the Leyden jar is used as a capacitor that is well known to those of ordinary skill in the relevant art.
In this manner, mechanical energy is converted to electrostatic energy. In prior applications of the Wimshurst generator, the amount of energy is increased by increasing the size of the disks. The efficiency of the system is also limited by the number of energy producing systems, there being only two in the above-described example. In other words, the induced charges have to remain on the charged sectors for a significant angular extent before they reach the next collector 41, 44. This leads to inefficiency because ionization losses occur during rotation. It would be greatly advantageous to provide a more efficient electrostatic generator with increased efficiency and energy capacity. In so doing, while the amount of mechanical energy required to operate the generator would increase, the physical apparatus could be more compact and robust. A more compact generator and robust unit could find uses where previously electrostatic generators of this type were too large.
There have been a few prior efforts to improve the efficiency of the basic Wimshurst generator. These include improvements such as disks rotating on a single shaft in the same direction, multiple stages of disks, and electrical contacts using conducting pulleys and embedded pellets. An example of all of these developments is described in U.S. Pat. No. 4,789,802 to Miyake. However, when produced with multiple stages, the Miyake generator is much larger and more complicated and more expensive than a Wimshurst generator of the same diameter. The Wimshurst generator, as well as another electrostatic generator known as the Van de Graf generator, are most commonly used to demonstrate electrical and physical phenomena to students. The Van de Graf generator is more commonly used because for a given size it generates greater electrostatic voltage. However, the Wimshurst machine is more easily constructed by students and educators and its components are visible, allowing a more thorough exploration of its function. The scientific and educational benefit of the device is only hampered by its complexity. It would be greatly advantageous to inventors, scientists, educators, students, and hobbyists to provide a more efficient Wimshurst-type electrostatic generator that Is smaller and no more complicated or expensive than the traditional Wimshurst generator.
It is, therefore, an object of the present invention to provide an electrostatic generator that increases the amount of electrostatic charge and electrostatic voltage differential that can be acquired in a compact apparatus.
It is another object to provide an inexpensive and facile electrostatic generator that can be constructed and operated by inventors to explore applications of electrostatic energy.
It is a further object to provide an electrostatic generator that readily demonstrates principles of electrostatic energy to students.
In accordance with the above objects, an improved high-voltage electrostatic generator is disclosed. The generator includes a pair of counter-rotating disks. Each disk has a plurality of charge plates angularly disposed about the periphery on one side, the charge plates on one disk facing those on the other. A plurality of grounding conductors with brushes at each end are associated with each of the disks, each grounding conductor alternately grounding a pair of opposing charge plates on each disk as it rotates. The generator also includes a pair of output terminals each having a brush at one end for electrical connection to the charge plates on one of the disks. Upon counter-rotation of the pair of disks, the grounding conductors neutralize each charge plate to accumulate a logarithmically-increasing charge until they are discharged to the next output terminal.